What total charge qq must be distributed uniformly over a spherical shell of radius R=0.30mR=0.30m to produce an electric field with magnitude 700 N/CN/C at a point just outside the surface of the shell?

7 x 10⁻⁹C

Inside the spherical shell, the electric field is zero, but outside the surface of the shell, the electric field (E) is given by;

E =            ----------------------(i)

Where;

k = proportionality constant = 9 x 10⁹Nm²/C²

Q = total charge over the spherical shell

r = the radius of the shell

From the question;

E = 700N/C

r = 0.30m

Substitute these values into equation (i) to get the total charge, Q, as follows;

700 =

700 =

700 x 0.09 = 9 x 10⁹ x Q

63 = 9 x 10⁹ x Q

Solve for Q;

Q = 63 / (9 x 10⁹)

Q = 7 x 10⁻⁹C

Therefore, the total charge is 7 x 10⁻⁹C

d. platinum would have the greatest temperature increase because it has the lowest specific heat.